The present invention generally relates to a liquid chromatography column assembly and, in particular, relates to such an assembly having means for establishing a sealed cylindrical cavity at one end thereof.
Most conventional liquid chromatography columns, during manufacture, are provided with end fittings which, in general, act to ensure the retention of the packing material. Usually, the packing material completely fills the column and is retained by the end fittings each of which includes a frit element. The frit element serves both as a seal against the loss of packing material and as a radial distribution element to distribute the incoming fluid substantially evenly across the cross-section of the column. In some commercial columns the frit is initially press-fit into the fitting before the fitting is placed on the column.
As a consequence of these manufacturing techniques the purchase price of a column must necessarily include the cost of the fittings. That is, whenever the useful life of a column expires a new set of fittings must also be purchased.
In recent years, throw-away cartridge columns have been introduced which do not require new fittings each time a column is replaced.
To date, however, such cartridge columns have exhibited a number of drawbacks. For example, some frit retainer arrangement has been required to properly position the frit and simultaneously retain the efficient radial distribution of fluid across the column.
One such assembly is described in U.S. Pat. No. 3,682,315 issued to Haller on Aug. 8, 1972. The assembly therein requires a self-sealing septum and includes a member extending into the column and to maintain a specific distance between the system and the frit. The member also acts to seal the column against leakage or loss of packing material. Such a member, in one form or another, is common in present cartridge column assemblies. In addition, the sealing of the column is somewhat complex. Thus, understandably, the cost of the column is still relatively high, and the assembly somewhat complex.